When someone sends texts with pictures to my iPad, the pictures show for a out 1/2 second and then disappear. They show up fine on my iPhone. any ideas?

A Month or so after upgrade my iPad will not show pictures received on iMessage. The text stays, but the pictures show for a split second and then disappear. The same txt and pic show (and stay!) on my iPhone, but not my iPad. The picture is immediately replaced by a small gray circular icon. I've. Even tried backing up, resetting and restoring. That worked for about 10 minutes, now back to the same problem. Any ideas?